A few months ago, I felt that the Democrats would have had a chance at picking up Arizona, Iowa and Missouri, but the Democrats chances at winning those seats have declined in my opinion. The reason why I don't see the Democrats picking up Arizona and Iowa is because both John McCain and Chuck Grassley have all but announced that they are running for re-election in 2016.
If anything, a John McCain run against a strong opponent like Synema or Carmona makes it an easier pick up. He's the most unpopular Senator in the country.
Your actually right, as according to several PPP polls, McCain is actually trailing the Democrats.